Articles | Volume 15, issue 2
https://doi.org/10.5194/cp-15-539-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-15-539-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
27 Mar 2019
Research article |
| 27 Mar 2019
| 27 Mar 2019
Insensitivity of alkenone carbon isotopes to atmospheric CO2 at low to moderate CO2 levels
Marcus P. S. Badger
CORRESPONDING AUTHOR
School of Environment, Earth & Ecosystem Sciences, The Open
University, Milton Keynes, MK7 6AA, UK
Organic Geochemistry Unit, School of Chemistry, School of Earth
Sciences, University of Bristol, Bristol, BS8 1TS, UK
Thomas B. Chalk
School of Ocean and Earth Science, National Oceanography Centre
Southampton, University of Southampton, Southampton, SO14 3ZH, UK
Department of Physical Oceanography, Woods Hole Oceanographic
Institution, Woods Hole, MA 02543, USA
Gavin L. Foster
School of Ocean and Earth Science, National Oceanography Centre
Southampton, University of Southampton, Southampton, SO14 3ZH, UK
Paul R. Bown
Department of Earth Sciences, University College London, London, WC1E
6BT, UK
Samantha J. Gibbs
School of Ocean and Earth Science, National Oceanography Centre
Southampton, University of Southampton, Southampton, SO14 3ZH, UK
Philip F. Sexton
School of Environment, Earth & Ecosystem Sciences, The Open
University, Milton Keynes, MK7 6AA, UK
Daniela N. Schmidt
School of Earth Sciences, University of Bristol, Wills Memorial
Building, Queens Road, Bristol, BS8 1RJ, UK
The Cabot Institute, University of Bristol, Bristol, BS8 1UJ, UK
Heiko Pälike
MARUM – Center for Marine Environmental Sciences, University of
Bremen, Bremen, Germany
Andreas Mackensen
Alfred Wegener Institute for Polar and Marine Research, Am Alten Hafen
26, Bremerhaven, Germany
Richard D. Pancost
Organic Geochemistry Unit, School of Chemistry, School of Earth
Sciences, University of Bristol, Bristol, BS8 1TS, UK
The Cabot Institute, University of Bristol, Bristol, BS8 1UJ, UK
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Paul J. Valdes, Edward Armstrong, Marcus P. S. Badger, Catherine D. Bradshaw, Fran Bragg, Michel Crucifix, Taraka Davies-Barnard, Jonathan J. Day, Alex Farnsworth, Chris Gordon, Peter O. Hopcroft, Alan T. Kennedy, Natalie S. Lord, Dan J. Lunt, Alice Marzocchi, Louise M. Parry, Vicky Pope, William H. G. Roberts, Emma J. Stone, Gregory J. L. Tourte, and Jonny H. T. Williams
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Understanding the boron isotopic composition of seawater (δ11Bsw) is key to calculating absolute estimates of CO2 using the boron isotope pH proxy. Here we use the boron isotope gradient, along with an estimate of pH gradient, between the surface and deep ocean to show that the δ11Bsw varies by ~ 2 ‰ over the past 23 million years. This new record has implications for both δ11Bsw and CO2 records and understanding changes in the ocean isotope composition of a number of ions through time.
Daniel J. Lunt, Matthew Huber, Eleni Anagnostou, Michiel L. J. Baatsen, Rodrigo Caballero, Rob DeConto, Henk A. Dijkstra, Yannick Donnadieu, David Evans, Ran Feng, Gavin L. Foster, Ed Gasson, Anna S. von der Heydt, Chris J. Hollis, Gordon N. Inglis, Stephen M. Jones, Jeff Kiehl, Sandy Kirtland Turner, Robert L. Korty, Reinhardt Kozdon, Srinath Krishnan, Jean-Baptiste Ladant, Petra Langebroek, Caroline H. Lear, Allegra N. LeGrande, Kate Littler, Paul Markwick, Bette Otto-Bliesner, Paul Pearson, Christopher J. Poulsen, Ulrich Salzmann, Christine Shields, Kathryn Snell, Michael Stärz, James Super, Clay Tabor, Jessica E. Tierney, Gregory J. L. Tourte, Aradhna Tripati, Garland R. Upchurch, Bridget S. Wade, Scott L. Wing, Arne M. E. Winguth, Nicky M. Wright, James C. Zachos, and Richard E. Zeebe
Geosci. Model Dev., 10, 889–901, https://doi.org/10.5194/gmd-10-889-2017, https://doi.org/10.5194/gmd-10-889-2017, 2017
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In this paper we describe the experimental design for a set of simulations which will be carried out by a range of climate models, all investigating the climate of the Eocene, about 50 million years ago. The intercomparison of model results is called 'DeepMIP', and we anticipate that we will contribute to the next IPCC report through an analysis of these simulations and the geological data to which we will compare them.
Marc Theodor, Gerhard Schmiedl, Frans Jorissen, and Andreas Mackensen
Biogeosciences, 13, 6385–6404, https://doi.org/10.5194/bg-13-6385-2016, https://doi.org/10.5194/bg-13-6385-2016, 2016
Mathieu Martinez, Sergey Kotov, David De Vleeschouwer, Damien Pas, and Heiko Pälike
Clim. Past, 12, 1765–1783, https://doi.org/10.5194/cp-12-1765-2016, https://doi.org/10.5194/cp-12-1765-2016, 2016
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Identification of Milankovitch cycles within the sedimentary record depends on spectral analyses, but these can be biased because there are always slight uncertainties in the sample position within a sedimentary column. Here, we simulate uncertainties in the sample position and show that a tight control on the inter-sample distance together with a density of 6–12 samples per precession cycle are needed to accurately reconstruct the contribution of the orbital forcing on past climate changes.
Pedro Alejandro Ruiz-Ortiz, José Manuel Castro, Ginés Alfonso de Gea, Ian Jarvis, José Miguel Molina, Luis Miguel Nieto, Richard David Pancost, María Luisa Quijano, Matías Reolid, Peter William Skelton, and Helmut Jürg Weissert
Sci. Dril., 21, 41–46, https://doi.org/10.5194/sd-21-41-2016, https://doi.org/10.5194/sd-21-41-2016, 2016
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The Cretaceous was punctuated by several episodes of accelerated global change, defined as Oceanic Anoxic Events (OAE), that reflect abrupt changes in global carbon cycling. In this progress report, we present a new drill core recovering an Aptian section spanning OAE1a in southern Spain. The Cau section is located in the easternmost part of the Prebetic Zone (Betic Cordillera). All the studies performed reveal that the Cau section represents an excellent site to further investigate OAE1a.
Daniel J. Lunt, Alex Farnsworth, Claire Loptson, Gavin L. Foster, Paul Markwick, Charlotte L. O'Brien, Richard D. Pancost, Stuart A. Robinson, and Neil Wrobel
Clim. Past, 12, 1181–1198, https://doi.org/10.5194/cp-12-1181-2016, https://doi.org/10.5194/cp-12-1181-2016, 2016
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We explore the influence of changing geography from the period ~ 150 million years ago to ~ 35 million years ago, using a set of 19 climate model simulations. We find that without any CO2 change, the global mean temperature is remarkably constant, but that regionally there are significant changes in temperature which we link back to changes in ocean circulation. Finally, we explore the implications of our findings for the interpretation of geological indicators of past temperatures.
Kimberley L. Davies, Richard D. Pancost, Mary E. Edwards, Katey M. Walter Anthony, Peter G. Langdon, and Lidia Chaves Torres
Biogeosciences, 13, 2611–2621, https://doi.org/10.5194/bg-13-2611-2016, https://doi.org/10.5194/bg-13-2611-2016, 2016
Claudia Agnini, David J. A. Spofforth, Gerald R. Dickens, Domenico Rio, Heiko Pälike, Jan Backman, Giovanni Muttoni, and Edoardo Dallanave
Clim. Past, 12, 883–909, https://doi.org/10.5194/cp-12-883-2016, https://doi.org/10.5194/cp-12-883-2016, 2016
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In this paper we present records of stable C and O isotopes, CaCO3 content, and changes in calcareous nannofossil assemblages in a upper Paleocene-lower Eocene rocks now exposed in northeast Italy. Modifications of nannoplankton assemblages and carbon isotopes are strictly linked one to each other and always display the same ranking and spacing. The integration of this two data sets represents a significative improvement in our capacity to correlate different sections at a very high resolution.
Matthew J. Carmichael, Daniel J. Lunt, Matthew Huber, Malte Heinemann, Jeffrey Kiehl, Allegra LeGrande, Claire A. Loptson, Chris D. Roberts, Navjit Sagoo, Christine Shields, Paul J. Valdes, Arne Winguth, Cornelia Winguth, and Richard D. Pancost
Clim. Past, 12, 455–481, https://doi.org/10.5194/cp-12-455-2016, https://doi.org/10.5194/cp-12-455-2016, 2016
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In this paper, we assess how well model-simulated precipitation rates compare to those indicated by geological data for the early Eocene, a warm interval 56–49 million years ago. Our results show that a number of models struggle to produce sufficient precipitation at high latitudes, which likely relates to cool simulated temperatures in these regions. However, calculating precipitation rates from plant fossils is highly uncertain, and further data are now required.
M. Wall, F. Ragazzola, L. C. Foster, A. Form, and D. N. Schmidt
Biogeosciences, 12, 6869–6880, https://doi.org/10.5194/bg-12-6869-2015, https://doi.org/10.5194/bg-12-6869-2015, 2015
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We investigated the ability of cold-water corals to deal with changes in ocean pH. We uniquely combined morphological assessment with boron isotope analysis to determine if changes in growth are related to changes in control of calcification pH. We found that the cold-water coral Lophelia pertusa can maintain the skeletal morphology, growth patterns as well as internal calcification pH. This has important implications for their future occurrence and explains their cosmopolitan distribution.
L. A. Melbourne, J. Griffin, D. N. Schmidt, and E. J. Rayfield
Biogeosciences, 12, 5871–5883, https://doi.org/10.5194/bg-12-5871-2015, https://doi.org/10.5194/bg-12-5871-2015, 2015
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Using Finite element modelling (FEM) we show that a simplified geometric FE model can predict the structural strength of the coralline algal skeleton. We compared a series of 3D geometric FE-models with increasing complexity to a biologically accurate model derived from computed tomography (CT) scan data. Using geometric models provides the basis for a better understanding of the potential effect of climate change on the structural integrity of these organisms.
K. H. Salmon, P. Anand, P. F. Sexton, and M. Conte
Biogeosciences, 12, 223–235, https://doi.org/10.5194/bg-12-223-2015, https://doi.org/10.5194/bg-12-223-2015, 2015
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Planktonic foraminifera are an important component of the marine carbon/carbonate cycle, yet the environmental controls on their abundances are still debated. In our study, we see larger foraminifera fluxes, particularly of heavy species, during winter when nutrients are mixed into the surface waters or during eddy mixing. Climatic factors that control mixing could therefore control the flux of planktonic foraminfera and the carbon/carbonate flux on seasonal and decadal timescales.
T. Westerhold, U. Röhl, H. Pälike, R. Wilkens, P. A. Wilson, and G. Acton
Clim. Past, 10, 955–973, https://doi.org/10.5194/cp-10-955-2014, https://doi.org/10.5194/cp-10-955-2014, 2014
L. Max, L. Lembke-Jene, J.-R. Riethdorf, R. Tiedemann, D. Nürnberg, H. Kühn, and A. Mackensen
Clim. Past, 10, 591–605, https://doi.org/10.5194/cp-10-591-2014, https://doi.org/10.5194/cp-10-591-2014, 2014
S. Romahn, A. Mackensen, J. Groeneveld, and J. Pätzold
Clim. Past, 10, 293–303, https://doi.org/10.5194/cp-10-293-2014, https://doi.org/10.5194/cp-10-293-2014, 2014
C. V. Davis, M. P. S. Badger, P. R. Bown, and D. N. Schmidt
Biogeosciences, 10, 6131–6139, https://doi.org/10.5194/bg-10-6131-2013, https://doi.org/10.5194/bg-10-6131-2013, 2013
A. G. M. Caromel, D. N. Schmidt, and J. C. Phillips
Biogeosciences Discuss., https://doi.org/10.5194/bgd-10-6763-2013, https://doi.org/10.5194/bgd-10-6763-2013, 2013
Revised manuscript not accepted
B. Rabe, P. A. Dodd, E. Hansen, E. Falck, U. Schauer, A. Mackensen, A. Beszczynska-Möller, G. Kattner, E. J. Rohling, and K. Cox
Ocean Sci., 9, 91–109, https://doi.org/10.5194/os-9-91-2013, https://doi.org/10.5194/os-9-91-2013, 2013
D. Liebrand, L. J. Lourens, D. A. Hodell, B. de Boer, R. S. W. van de Wal, and H. Pälike
Clim. Past, 7, 869–880, https://doi.org/10.5194/cp-7-869-2011, https://doi.org/10.5194/cp-7-869-2011, 2011
Daniela N. Schmidt, Jeremy R. Young, Shirley Van Heck, and Jackie Lees
J. Micropalaeontol., 28, 91–93, https://doi.org/10.1144/jm.28.1.91, https://doi.org/10.1144/jm.28.1.91, 2009
Related subject area
Subject: Proxy Use-Development-Validation | Archive: Marine Archives | Timescale: Pleistocene
Monsoon-driven changes in aeolian and fluvial sediment input to the central Red Sea recorded throughout the last 200 000 years
Orbital CO2 reconstruction using boron isotopes during the late Pleistocene, an assessment of accuracy
Bayesian age models and stacks: combining age inferences from radiocarbon and benthic δ18O stratigraphic alignment
A 600 kyr reconstruction of deep Arctic seawater δ18O from benthic foraminiferal δ18O and ostracode Mg ∕ Ca paleothermometry
Antarctic sea ice over the past 130 000 years – Part 1: a review of what proxy records tell us
Reorganization of Atlantic Waters at sub-polar latitudes linked to deep-water overflow in both glacial and interglacial climate states
Parallel between the isotopic composition of coccolith calcite and carbon levels across Termination II: developing a new paleo-CO2 probe
A global climatology of the ocean surface during the Last Glacial Maximum mapped on a regular grid (GLOMAP)
Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic
Modal shift in North Atlantic seasonality during the last deglaciation
Technical note: PaleoDataView – a software toolbox for the collection, homogenization and visualization of marine proxy data
Sensitivity to species selection indicates the effect of nuisance variables on marine microfossil transfer functions
Extreme lowering of deglacial seawater radiocarbon recorded by both epifaunal and infaunal benthic foraminifera in a wood-dated sediment core
A Late Quaternary climate record based on long-chain diol proxies from the Chilean margin
Moving beyond the age–depth model paradigm in deep-sea palaeoclimate archives: dual radiocarbon and stable isotope analysis on single foraminifera
Quantifying the effect of seasonal and vertical habitat tracking on planktonic foraminifera proxies
Water and carbon stable isotope records from natural archives: a new database and interactive online platform for data browsing, visualizing and downloading
Palaeo-sea-level and palaeo-ice-sheet databases: problems, strategies, and perspectives
Multiproxy reconstruction for Kuroshio responses to northern hemispheric oceanic climate and the Asian Monsoon since Marine Isotope Stage 5.1 (∼88 ka)
Hydrographic changes in the Agulhas Recirculation Region during the late Quaternary
Salinity changes in the Agulhas leakage area recorded by stable hydrogen isotopes of C37 alkenones during Termination I and II
Mismatch between the depth habitat of planktonic foraminifera and the calibration depth of SST transfer functions may bias reconstructions
Werner Ehrmann, Paul A. Wilson, Helge W. Arz, Hartmut Schulz, and Gerhard Schmiedl
Clim. Past, 20, 37–52, https://doi.org/10.5194/cp-20-37-2024, https://doi.org/10.5194/cp-20-37-2024, 2024
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Climatic and associated hydrological changes controlled the aeolian versus fluvial transport processes and the composition of the sediments in the central Red Sea through the last ca. 200 kyr. We identify source areas of the mineral dust and pulses of fluvial discharge based on high-resolution grain size, clay mineral, and geochemical data, together with Nd and Sr isotope data. We provide a detailed reconstruction of changes in aridity/humidity.
Elwyn de la Vega, Thomas B. Chalk, Mathis P. Hain, Megan R. Wilding, Daniel Casey, Robin Gledhill, Chongguang Luo, Paul A. Wilson, and Gavin L. Foster
Clim. Past, 19, 2493–2510, https://doi.org/10.5194/cp-19-2493-2023, https://doi.org/10.5194/cp-19-2493-2023, 2023
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We evaluate how faithfully the boron isotope composition of foraminifera records atmospheric CO2 by comparing it to the high-fidelity CO2 record from the Antarctic ice cores. We evaluate potential factors and find that partial dissolution of foraminifera shells, assumptions of seawater chemistry, and the biology of foraminifera all have a negligible effect on reconstructed CO2. This gives confidence in the use of boron isotopes beyond the interval when ice core CO2 is available.
Taehee Lee, Devin Rand, Lorraine E. Lisiecki, Geoffrey Gebbie, and Charles Lawrence
Clim. Past, 19, 1993–2012, https://doi.org/10.5194/cp-19-1993-2023, https://doi.org/10.5194/cp-19-1993-2023, 2023
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Understanding of past climate change depends, in part, on how accurately we can estimate the ages of events recorded in geologic archives. Here we present a new software package, called BIGMACS, to improve age estimates for paleoclimate data from ocean sediment cores. BIGMACS creates multiproxy age estimates that reduce age uncertainty by probabilistically combining information from direct age estimates, such as radiocarbon dates, and the alignment of regional paleoclimate time series.
Jesse R. Farmer, Katherine J. Keller, Robert K. Poirier, Gary S. Dwyer, Morgan F. Schaller, Helen K. Coxall, Matt O'Regan, and Thomas M. Cronin
Clim. Past, 19, 555–578, https://doi.org/10.5194/cp-19-555-2023, https://doi.org/10.5194/cp-19-555-2023, 2023
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Oxygen isotopes are used to date marine sediments via similar large-scale ocean patterns over glacial cycles. However, the Arctic Ocean exhibits a different isotope pattern, creating uncertainty in the timing of past Arctic climate change. We find that the Arctic Ocean experienced large local oxygen isotope changes over glacial cycles. We attribute this to a breakdown of stratification during ice ages that allowed for a unique low isotope value to characterize the ice age Arctic Ocean.
Xavier Crosta, Karen E. Kohfeld, Helen C. Bostock, Matthew Chadwick, Alice Du Vivier, Oliver Esper, Johan Etourneau, Jacob Jones, Amy Leventer, Juliane Müller, Rachael H. Rhodes, Claire S. Allen, Pooja Ghadi, Nele Lamping, Carina B. Lange, Kelly-Anne Lawler, David Lund, Alice Marzocchi, Katrin J. Meissner, Laurie Menviel, Abhilash Nair, Molly Patterson, Jennifer Pike, Joseph G. Prebble, Christina Riesselman, Henrik Sadatzki, Louise C. Sime, Sunil K. Shukla, Lena Thöle, Maria-Elena Vorrath, Wenshen Xiao, and Jiao Yang
Clim. Past, 18, 1729–1756, https://doi.org/10.5194/cp-18-1729-2022, https://doi.org/10.5194/cp-18-1729-2022, 2022
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Despite its importance in the global climate, our knowledge of Antarctic sea-ice changes throughout the last glacial–interglacial cycle is extremely limited. As part of the Cycles of Sea Ice Dynamics in the Earth system (C-SIDE) Working Group, we review marine- and ice-core-based sea-ice proxies to provide insights into their applicability and limitations. By compiling published records, we provide information on Antarctic sea-ice dynamics over the past 130 000 years.
Dakota E. Holmes, Tali L. Babila, Ulysses Ninnemann, Gordon Bromley, Shane Tyrrell, Greig A. Paterson, Michelle J. Curran, and Audrey Morley
Clim. Past, 18, 989–1009, https://doi.org/10.5194/cp-18-989-2022, https://doi.org/10.5194/cp-18-989-2022, 2022
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Our proxy-based observations of the glacial inception following MIS 11 advance our mechanistic understanding of (and elucidates antecedent conditions that can lead to) high-magnitude climate instability during low- and intermediate-ice boundary conditions. We find that irrespective of the magnitude of climate variability or boundary conditions, the reorganization between Polar Water and Atlantic Water at subpolar latitudes appears to influence deep-water flow in the Nordic Seas.
Camille Godbillot, Fabrice Minoletti, Franck Bassinot, and Michaël Hermoso
Clim. Past, 18, 449–464, https://doi.org/10.5194/cp-18-449-2022, https://doi.org/10.5194/cp-18-449-2022, 2022
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We test a new method to reconstruct past atmospheric CO2 levels based on the geochemistry of pelagic algal biominerals (coccoliths), which recent culture and numerical experiments have related to ambient CO2 concentrations. By comparing the isotopic composition of fossil coccoliths to the inferred surface ocean CO2 level at the time they calcified, we outline a transfer function and argue that coccolith vital effects can be used to reconstruct geological pCO2 beyond the ice core record.
André Paul, Stefan Mulitza, Rüdiger Stein, and Martin Werner
Clim. Past, 17, 805–824, https://doi.org/10.5194/cp-17-805-2021, https://doi.org/10.5194/cp-17-805-2021, 2021
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Maps and fields of near-sea-surface temperature differences between the past and present can be used to visualize and quantify climate changes and perform simulations with climate models. We used a statistical method to map sparse and scattered data for the Last Glacial Maximum time period (23 000 to 19 000 years before present) to a regular grid. The estimated global and tropical cooling would imply an equilibrium climate sensitivity in the lower to middle part of the currently accepted range.
Leticia G. Luz, Thiago P. Santos, Timothy I. Eglinton, Daniel Montluçon, Blanca Ausin, Negar Haghipour, Silvia M. Sousa, Renata H. Nagai, and Renato S. Carreira
Clim. Past, 16, 1245–1261, https://doi.org/10.5194/cp-16-1245-2020, https://doi.org/10.5194/cp-16-1245-2020, 2020
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Two sediment cores retrieved from the SE Brazilian continental margin were studied using multiple organic (alkenones) and inorganic (oxygen isotopes in carbonate shells and water) proxies to reconstruct the sea surface temperature (SST) over the last 50 000 years. The findings indicate the formation of strong thermal gradients in the region during the last climate transition, a feature that may become more frequent in the future scenario of global water circulation changes.
Geert-Jan A. Brummer, Brett Metcalfe, Wouter Feldmeijer, Maarten A. Prins, Jasmijn van 't Hoff, and Gerald M. Ganssen
Clim. Past, 16, 265–282, https://doi.org/10.5194/cp-16-265-2020, https://doi.org/10.5194/cp-16-265-2020, 2020
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Here, mid-ocean seasonality is resolved through time, using differences in the oxygen isotope composition between individual shells of the commonly used (sub)polar planktonic foraminifera species in ocean-climate reconstruction, N. pachyderma and G. bulloides. Single-specimen isotope measurements during the deglacial period revealed a surprising bimodality, the cause of which was investigated.
Michael Langner and Stefan Mulitza
Clim. Past, 15, 2067–2072, https://doi.org/10.5194/cp-15-2067-2019, https://doi.org/10.5194/cp-15-2067-2019, 2019
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Collections of paleoclimate data provide valuable information on the functioning of the Earth system but are often difficult to manage due to the inconsistency of data formats and reconstruction methods. We present a software toolbox that combines a simple document-based database with functionality for the visualization and management of marine proxy data. The program allows the efficient homogenization of larger paleoceanographic data sets into quality-controlled and transparent data products.
Lukas Jonkers and Michal Kučera
Clim. Past, 15, 881–891, https://doi.org/10.5194/cp-15-881-2019, https://doi.org/10.5194/cp-15-881-2019, 2019
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Fossil plankton assemblages have been widely used to reconstruct SST. In such approaches, full taxonomic resolution is often used. We assess whether this is required for reliable reconstructions as some species may not respond to SST. We find that only a few species are needed for low reconstruction errors but that species selection has a pronounced effect on reconstructions. We suggest that the sensitivity of a reconstruction to species pruning can be used as a measure of its robustness.
Patrick A. Rafter, Juan-Carlos Herguera, and John R. Southon
Clim. Past, 14, 1977–1989, https://doi.org/10.5194/cp-14-1977-2018, https://doi.org/10.5194/cp-14-1977-2018, 2018
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Carbon’s radioactive isotope (radiocarbon) is a useful tool for oceanographers investigating carbon cycling in the modern ocean and ice age oceans (using foraminifera microfossils). Here we used sediment cores with excellent age constraints and abundant foraminifera microfossils to examine interspecies radiocarbon differences. All species demonstrate the same extreme radiocarbon depletion, and we argue that these observations represent important changes in seawater carbon chemistry.
Marijke W. de Bar, Dave J. Stolwijk, Jerry F. McManus, Jaap S. Sinninghe Damsté, and Stefan Schouten
Clim. Past, 14, 1783–1803, https://doi.org/10.5194/cp-14-1783-2018, https://doi.org/10.5194/cp-14-1783-2018, 2018
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We present a past sea surface temperature and paleoproductivity record over the last 150 000 years for ODP Site 1234 (Chilean margin). We tested the applicability of long-chain diol proxies for the reconstrucion of SST (LDI), past upwelling conditions (diol index), and nutrient concentrations (NDI). The LDI likely reflects past temperature changes, but the diol index and NDI are perhaps more indicative of Proboscia diatom productivity rather than upwelling and/or nutrient conditions.
Bryan C. Lougheed, Brett Metcalfe, Ulysses S. Ninnemann, and Lukas Wacker
Clim. Past, 14, 515–526, https://doi.org/10.5194/cp-14-515-2018, https://doi.org/10.5194/cp-14-515-2018, 2018
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Palaeoclimate reconstructions from deep-sea sediment archives provide valuable insight into past rapid climate change, but only a small proportion of the ocean is suitable for such reconstructions using the existing state of the art, i.e. the age–depth approach. We use dual radiocarbon (14C) and stable isotope analysis on single foraminifera to bypass the long-standing age–depth approach, thus facilitating past ocean chemistry reconstructions from vast, previously untapped ocean areas.
Lukas Jonkers and Michal Kučera
Clim. Past, 13, 573–586, https://doi.org/10.5194/cp-13-573-2017, https://doi.org/10.5194/cp-13-573-2017, 2017
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Planktonic foraminifera – the most important proxy carriers in palaeoceanography – adjust their seasonal and vertical habitat. They are thought to do so in a way that minimises the change in their environment, implying that proxy records based on these organisms may not capture the full amplitude of past climate change. Here we demonstrate that they indeed track a particular thermal habitat and suggest that this could lead to a 40 % underestimation of reconstructed temperature change.
Timothé Bolliet, Patrick Brockmann, Valérie Masson-Delmotte, Franck Bassinot, Valérie Daux, Dominique Genty, Amaelle Landais, Marlène Lavrieux, Elisabeth Michel, Pablo Ortega, Camille Risi, Didier M. Roche, Françoise Vimeux, and Claire Waelbroeck
Clim. Past, 12, 1693–1719, https://doi.org/10.5194/cp-12-1693-2016, https://doi.org/10.5194/cp-12-1693-2016, 2016
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This paper presents a new database of past climate proxies which aims to facilitate the distribution of data by using a user-friendly interface. Available data from the last 40 years are often fragmented, with lots of different formats, and online libraries are sometimes nonintuitive. We thus built a new dynamic web portal for data browsing, visualizing, and batch downloading of hundreds of datasets presenting a homogeneous format.
André Düsterhus, Alessio Rovere, Anders E. Carlson, Benjamin P. Horton, Volker Klemann, Lev Tarasov, Natasha L. M. Barlow, Tom Bradwell, Jorie Clark, Andrea Dutton, W. Roland Gehrels, Fiona D. Hibbert, Marc P. Hijma, Nicole Khan, Robert E. Kopp, Dorit Sivan, and Torbjörn E. Törnqvist
Clim. Past, 12, 911–921, https://doi.org/10.5194/cp-12-911-2016, https://doi.org/10.5194/cp-12-911-2016, 2016
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This review/position paper addresses problems in creating new interdisciplinary databases for palaeo-climatological sea-level and ice-sheet data and gives an overview on new advances to tackle them. The focus therein is to define and explain strategies and highlight their importance to allow further progress in these fields. It also offers important insights into the general problem of designing competitive databases which are also applicable to other communities within the palaeo-environment.
X. Shi, Y. Wu, J. Zou, Y. Liu, S. Ge, M. Zhao, J. Liu, A. Zhu, X. Meng, Z. Yao, and Y. Han
Clim. Past, 10, 1735–1750, https://doi.org/10.5194/cp-10-1735-2014, https://doi.org/10.5194/cp-10-1735-2014, 2014
D. K. Naik, R. Saraswat, N. Khare, A. C. Pandey, and R. Nigam
Clim. Past, 10, 745–758, https://doi.org/10.5194/cp-10-745-2014, https://doi.org/10.5194/cp-10-745-2014, 2014
S. Kasper, M. T. J. van der Meer, A. Mets, R. Zahn, J. S. Sinninghe Damsté, and S. Schouten
Clim. Past, 10, 251–260, https://doi.org/10.5194/cp-10-251-2014, https://doi.org/10.5194/cp-10-251-2014, 2014
R. J. Telford, C. Li, and M. Kucera
Clim. Past, 9, 859–870, https://doi.org/10.5194/cp-9-859-2013, https://doi.org/10.5194/cp-9-859-2013, 2013
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Short summary
Understanding how atmospheric CO2 has affected the climate of the past is an important way of furthering our understanding of how CO2 may affect our climate in the future. There are several ways of determining CO2 in the past; in this paper, we ground-truth one method (based on preserved organic matter from alga) against the record of CO2 preserved as bubbles in ice cores over a glacial–interglacial cycle. We find that there is a discrepancy between the two.
Understanding how atmospheric CO2 has affected the climate of the past is an important way of...
